Under Greek influence, he was identified with Hippolytus, who after he had been trampled to death by the horses of Poseidon was restored to life by Asclepius and removed by Artemis to the grove at Aricia, which horses were not allowed to enter.
His identification with Hippolytus and the manner of the latter's death would explain the exclusion of horses from his grove.
The chief uncertainty is as to whether he knew Justin's Syntagma, and also as to whether he had access to the Philosophumena of Hippolytus in their complete form.
Hippolytus (Legend) >>
Closely related to this is the account in the Syntagma of Hippolytus, which is preserved in Epiphanius, Haer.